Questions 39-50
The US manned space flight program of the 1960s and 1970s consisted of three distinct phases: Mercury, Gemini and Apollo. Each of these distinct phases of the space flight program served a very different purpose.
Mercury was the first phase of the manned space flight program. Its purpose was to get a person into orbital flight. The tiny Mercury capsule carried only a single astronaut. Alan Shepard and Virgil Grissom piloted the first two Mercury flights, which were suborbital flights, in 1961. John Glenn, in the next Mercury flight, orbited the Earth in 1962. Three more Mercury flights followed.
The next phase of the manned space flight program was Gemini. The purpose of the ten CREWED Gemini flights in 1965 and 1966 was to conduct training tests necessary for longer space flights. Gemini, for example, carried out training in orbital clocking techniques and tests of the effects of long-term weightlessness on astronauts. Unlike Mercury capsules, which held only one astronaut, the Gemini capsules were designed to carry two astronauts. The name Gemini was taken from the name of constellation, which means “twins”.
The Apollo flights followed the Gemini flights with the goal of landing astronauts on the Moon. The Apollo spacecraft consisted of three modules. The command module carried three astronauts to and from the Moon, the service module housed the propulsion and environmental systems, and the lunar module separated from the command module to land astronauts on the Moon. There were seventeen total Apollo flights, of which the first six carried no crew. The seventh through tenth Apollo flights (1968-1969) CIRCUMNAVIGATED the Moon without landing and then returned to Earth. The next seven Apollo flights (1969-1972) were intended to land on the Moon. All of them did, except Apollo 13, which developed serious problems and had to ABORT the intended landing but still managed to return safely to Earth.
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